Flutter app modernization for teams that cannot afford downtime
If your iOS and Android apps feel slow to change, fragile to release, and expensive to maintain, you are not alone. Many teams reach a point where keeping two native stacks alive is blocking growth. Our Flutter App Modernization & Migration Services are built for product and engineering leaders who want one codebase, predictable releases, and a clearly better user experience without putting revenue at risk.
BYBOWU is a Phoenix, AZ based web and mobile app agency working with US and international companies that rely on their apps for sales, operations, and customer loyalty. We join your team as senior Flutter engineers and product partners, so modernization becomes a controlled project, not a gamble.
The problems we fix when we move you to Flutter
If any of this sounds familiar, your app is probably overdue for a serious update:
- Two apps, two teams, double the work: iOS and Android features drift, defects show up differently on each platform, and every roadmap change takes twice the effort.
- Legacy stacks blocking hiring: Old Swift/Objective-C, Java, or hybrid stacks are harder to staff and slow to extend.
- Sluggish, unreliable experience: Slow cold starts, janky scrolling, crashes, and battery drain that hurt ratings and retention.
- Release days that feel risky: Manual builds, fragile pipelines, last-minute hotfixes, and no clear view of release health.
- Inconsistent UX: Different flows, visuals, and edge cases between platforms that make the product feel less trustworthy.
The real cost is not just technical debt. It is slower feature delivery, more stress on the team, and leadership losing confidence in the roadmap.
The solution: one modern Flutter codebase, designed for growth
We do not simply port screens. We rebuild your mobile layer around Flutter so it is faster to ship, easier to reason about, and ready for the next few years of product changes.
- Clean architecture and state management: Layered architecture (domain, data, presentation) with BLoC or Riverpod, dependency injection, feature modules, robust error handling, and offline-safe flows.
- Consistent UI/UX and design system: Shared component library, design tokens, light/dark themes, motion, and accessibility built on Material 3 and Cupertino. Golden tests keep visual regressions from slipping through.
- Solid data layer and integrations: Structured REST or GraphQL APIs, caching, secure storage, analytics, and event tracking that do not drag down performance.
- Native capabilities preserved: Payments, maps, camera, biometrics, Bluetooth, streaming, and other SDKs wired via Platform Channels or Pigeon, with clear boundaries so updates stay predictable.
- Quality built in from day one: Unit, widget, and integration tests, static analysis, and automated pipelines so each release is repeatable instead of a fire drill.
The outcome: one Flutter codebase serving iOS and Android today, with the option to extend to web or desktop later if the product strategy calls for it.
How our Flutter migration process works
Every legacy app is different. Our job is to move you to Flutter with visible progress early, clear milestones, and no surprises on risk, cost, or timing.
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1. Discovery and technical audit
We review your existing iOS and Android codebases, crash logs, performance metrics, monitoring stack, and release process. Together we agree on the business metrics that matter most, such as activation, retention, support volume, or revenue, so modernization is tied to concrete outcomes.
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2. Architecture design and migration strategy
We define the target Flutter architecture, select BLoC or Riverpod, design navigation, module boundaries, and API contracts, then choose the safest migration path:
- Add-to-app: Introduce Flutter modules inside your existing native shells to de-risk the move while production stays live.
- Greenfield Flutter app: Build a new Flutter app alongside the legacy stack and migrate flows or user groups in stages.
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3. Incremental delivery of high-impact flows
We start with flows that matter most to your business, such as onboarding, search, product discovery, checkout, or account. Stakeholders see performance and UX improvements quickly, not at the end of a long rewrite.
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4. Performance optimization
Using Flutter DevTools and release analytics, we tune build sizes, rendering, and network behavior. Heavy work moves to isolates or native, shader warm-up and other techniques reduce jank, and we keep memory and battery usage in check.
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5. Quality, security, and compliance
We add automated tests, static analysis, secure storage, and runtime checks where appropriate. Release health, crash analytics, and performance dashboards make it clear when a build is safe to ship and how it behaves in the wild.
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6. CI/CD and launch
We set up or refine pipelines with tools like GitHub Actions, Codemagic, and fastlane, configure beta channels (TestFlight, Play Internal), and use staged rollouts to minimize risk. Releases go from multi-week events to a repeatable process.
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7. Handover and ongoing support
We document the architecture, decisions, and workflows, then train your internal team if you have one. BYBOWU can stay on as a feature squad or provide structured maintenance and support when you need extra senior capacity.
Talk to us about your current app and we will outline a migration plan, timeline, and budget range you can take back to your leadership team.
What you get from a Flutter modernization, in real terms
- Better performance where users notice it: Faster app launches, smoother scrolling and animations, fewer crashes and ANRs, and more efficient battery usage.
- Higher delivery velocity: One backlog and one codebase, so features ship to iOS and Android in the same sprint instead of staggering releases.
- Lower maintenance overhead: Typed Dart with null safety, modular architecture, shared components, and tests that catch regressions before they hit the store.
- More predictable costs: Less duplicated work, fewer emergency patch cycles, and more development time going into features that actually move KPIs.
- A platform you can grow with: Room to add web or desktop, plug in AI or backend changes, or expand to new markets without starting from scratch again.
What you can order
- Flutter Readiness Audit — A focused review of your current iOS and Android apps, architecture, and roadmap with a written recommendation on whether Flutter migration makes sense, estimated effort, and key risks.
- Add-to-App Pilot Module — Implementation of one contained flow (for example onboarding, login, or account) in Flutter inside your existing native app to validate performance, UX, and integration.
- Core Flows Migration — Migration of a set of high-value flows like search, catalog, or checkout into Flutter, with CI/CD, analytics, and monitoring in place so you can measure impact immediately.
- Full Flutter Rebuild — End-to-end design and implementation of a new Flutter app that replaces your legacy stacks, including architecture, UI, integrations, testing, and launch support.
- Flutter Performance and Stability Tune-Up — For existing Flutter apps, a structured optimization engagement focused on performance issues, crash reduction, and release quality.
- Managed Flutter Squad — A senior BYBOWU team embedded with your product group to own ongoing Flutter development, mentoring, and complex integrations.
Why choose BYBOWU for Flutter app modernization
- Migration without drama — We have real experience untangling legacy systems, not just building greenfield demos. We design migrations to run alongside your current roadmap instead of freezing it.
- Product and engineering in the same room — We understand that activation, retention, support load, and revenue matter just as much as code quality. Every decision is tied back to measurable outcomes.
- Senior talent only — You work with experienced engineers and designers, not a rotating cast of juniors. That means fewer surprises, more stable releases, and a codebase your team can own.
- Global collaboration, local accountability — Headquartered in Phoenix and working with teams across the US and worldwide, we are used to clear communication, shared documentation, and overlapping hours that keep work moving.
- Long-term partnership if you want it — Many clients keep us involved after launch for mobile app development, performance tuning, and new initiatives, so your investment keeps paying off.
Proof it works in the real world
Marketplace app, modernized for growth
A retail marketplace that outgrew its first-generation stack needed smoother browsing and faster releases. We reworked the architecture and mobile experience so new campaigns and product lines could go live without long app store delays.
Roommate matching platform
A housing and roommate matching product relied heavily on in-app onboarding and messaging. We improved the app experience to reduce drop-offs in key flows and made it easier for the internal team to test and launch updates.
Wholesale and dropshipping tools
A B2B ecommerce platform serving wholesalers and dropshippers needed more stable mobile workflows. We helped streamline complex flows and integrations so the team could focus on expanding features instead of fighting regressions.
How engagement with BYBOWU works
We aim to be a practical partner, not another vendor adding noise to your backlog. Here is how a typical engagement looks.
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Initial consultation (30–45 minutes)
We talk through your apps, roadmap, constraints, and success metrics. If Flutter is not the right move, we will say so and point to better options such as React Native or targeted backend work.
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Technical review and estimate
With access to your repositories and tooling, we run a focused audit. Within a few business days you get a phased plan, realistic timeline, and a budget range with clear tradeoffs.
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Pilot phase
We start with a contained module to prove out the architecture, integration pattern, and working relationship. You get a real feature in production, not just a prototype.
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Full migration and optimization
Once the pilot is successful, we expand the Flutter footprint feature by feature, keep performance tuned, and refine CI/CD so your releases become boring in the best way.
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Ongoing partnership (optional)
If it makes sense, we stay on as your senior Flutter team, owning roadmap slices, mentoring in-house developers, and handling complex integrations and experiments.
Whether you are based in the US or overseas, we are comfortable working across time zones and integrating with existing product and engineering teams.
Request a Flutter modernization call and we will help you understand options, risks, and likely timelines before you commit.
Questions founders usually ask
What budgets do Flutter migrations typically require?
Costs depend heavily on app size, integrations, and how much of the UX you want to rethink. A small pilot or single-flow migration can fit into a modest project budget. A full rebuild of a complex consumer or enterprise app is a more substantial investment, usually spread over multiple phases. After an initial audit we provide a clear range with options.
How long does it take to move from native to Flutter?
A narrow pilot can ship in a few weeks. A focused set of core flows may take a couple of months. A full migration of a large app is often structured as a multi-month program with clear milestones. We will align timelines with your release calendar so you are not forced into risky cutovers.
Do we have to rewrite everything at once?
No. In fact, we prefer staged migration. Using add-to-app, we can introduce Flutter alongside existing native code and move flow by flow. That keeps production stable, lets you compare behavior directly, and avoids a big-bang rewrite that delays value for months.
Will we lose any native capabilities by moving to Flutter?
For most use cases, no. Flutter exposes native capabilities through Platform Channels or Pigeon, and many SDKs already have quality Flutter plugins. For niche or complex hardware cases, we can keep certain parts in native and connect them cleanly to the Flutter app.
Can your team work with our in-house developers?
Yes. Many of our projects pair BYBOWU engineers with internal teams. We are comfortable owning architecture, setting up patterns, and then coaching your team so they can take over confidently once the migration is complete.
What happens after launch?
You choose. Some clients take full ownership using the documentation and training we provide. Others keep us on for structured support, performance tuning, and ongoing product work. In both cases we aim for a codebase that is easy to maintain, not something you are locked into.
If you are ready to explore a move to Flutter, or just want a second opinion on your current mobile architecture, email [email protected] or use our contact form to request a Flutter migration review. You can also browse our portfolio to see how we approach complex web and mobile projects.
